Personally, I love horror comedy. I find a good one endlessly rewatchable. Cabin in the Woods, Return of the Living Dead, Tucker & Dale, Scream, frigging Killer Klowns from Outer Space! Definitely my favorite.
Otherwise I’m really into paranormal & zombie horror. I think that would make up my top three. Fast > slow zombies.
Science Fiction horror. There are so few movies that do it right. I don’t want to see a goofy monster chasing people around a ship. I want to feel the dread and helplessness of being isolated in the emptiness of space and having to deal with some unknown horror. A big part of the fun is the mystery and the endless possibilities.
Firefly does a good job of this with its Blue Gloves, Jubal Early, Adelai Niska, and Reavers. They’re the worst kind of monsters—human ones.
Also Twilight Zone (Peele series), Six Degrees of Freedom is fantastic existential scifi horror.
I love a good science fiction that’s just beyond reality. Things that could actually happen in the real world with a not-too-unlikely dice roll.
The Last Of Us for example: a known, real-world fungal spore that takes over its hosts body (ants) and uses it to attack and spread to other potential hosts; mutates to survive earth’s rising temperatures allowing it to survive in and control larger warm-blooded hosts (humans).
Thus, real zombies that aren’t the result of some total fantasy fabricated in a lab that fucked up somewhere.
It’s more believable making the fear more real.